Device for resuperheating steam in prime movers



F. HOULET 2,509,302

DEVICE FOR RESUPERHEATING STEAM IN PRIME MOVERS May 30, 1950 2 Sheets-Sheet 1 Filed June 28, 1945 my 30, 1950 F. HOULET 2,509,302

- DEVICE FOR RESUPERl-IEATING STEAM IN PRIME MOVERS Filed June 28, 1945 2 Sheets-Sheet 2 fatented May 30, 1950 UNITED DEVICE FOR RESUPERHEATING STEAM IN PRIIVIE MOVERS Flix Houlet, Paris, France Application June 28, 1945, Serial No. 602,125 In France September 29, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires September 29, 1961 6 Claims.

In single or multiple-expansion steam engines, it is found that the fluid at the end of the final expansion, is a mixture of steam and water, even when the steam utilized is initially in the superheated iorm. That is Why, in multiple-expansion engines, it has been attempted, repeatedly, to take advantage of the fact that the fiuid can be trapped between two expansion stages to superheat it again.

But the problem thus set down encounters, in practice, difiiculties which, up to now, have delayed the generalisation of the method, mainly in the case when, as on locomotives, for instance, for the evaporating and superheating apparatus, only a, restricted space is available.

In this latter case, which is that of double expansion, the high pressure superheating elements are placed in tubes ad-hoc, which occupy up to two-thirds of the nest of tubes. It will therefore be understood that with conventional ar rangements, it is impossible to maintain, on the one hand, the totality of the elements reserved for high pressure, and on the other hand, to have available, solely for low pressure, a number of supplementary elements sufiicient for re-superheating the steam at low pressure, the specific volume of which is, at this stage, about four times greater, than for high pressure.

It will immediately be seen that, as a sufiicient number of elements is not reserved for this latter use, an insufficient section of passageway is offered to the low pressure steam, inevitably in volving losses of head which, up to now, are absolutely prohibitive.

The present invention has for its object to effect resuperheating between two expansion stages, whilst involving only an acceptable loss of head.

For that purpose, in a first embodiment, the invention consists in taking advantage of the possibility of utilising a certain number of supple- .mentary elements, identical to those used for high pressure (elements consequently giving a high temperature), by leading to this nest of tubes but a fraction of the steam to be re-superheated. By mixing said steam with nonresuperheated steam, a whole is thus obtained the temperature of which is suitable for low pressure. As the circulation of the fraction of resuperheated steam can only take place in the corresponding elements provided that a supplementary amount of energy is added necessary for overcoming the passive resistances, a. circulation pump is arranged for instance, on the path of the deflected steam.

In the accompanying drawing, Fig. 1 illustrates, in longitudinal section, an arrangement of this kind and Fig. 2 shows in the same way a second arrangement.

Saturated steam is admitted through the pipe I in the saturated steam chamber 2 of the manifold; from there it is led through 3 towards the superheater 4, which is of the annular type in this example; it issues therefrom in a superheated state through pipe 5 which leads it to the superheated steam chamber 6 of the manifold. The superheated steam passes through 1 to the high pressure cylinders. It issues therefrom through pipe-line 8 which opens into an intermediate tank 9.

It is at this point that, according to the device forming the subject-matter of the invention, is provided a by-pass it] towards the re-superheater. I l is a circulation pump.

2 is a chamber for steam to be re-superheated, wherefrom a pipe l4 leads said steam to an annular re-superheater l5; it issues therefrom resuperheated through [6 which leads it to chamber l3; I1 is the return pipe for said re-superheated fraction to tank 9, Where a mixture at a suitable temperature of superheated and re-superheated steam is thus formed which flows through l8 towards the low pressure cylinders.

In order to avoid the complication of the circulation pump or other equivalent means, a second embodiment of the invention has been devised according to the following methods:

Some types of superheaters are so devised that the active part of their elements is arranged in the vicinity of the furnace. Such is the case, in

particular, of a special form of superheater known under the name of annular superheater, which presents, in it half nearer the smoke box, only two connection tubes, thus providing an available space in the smoke tube which can receive, for instance, two other tubes forming the simple loop of a shortened superheating element independent from the first one.

elements. be the same at the outlet of each type of element,

I9 is the smoke tube of the dimension necessary for receiving one of the n high pressure superheating elements 20, for instance, of annular type, with its steam inlet tube 23, issuing from the saturated steam manifold 24 and its outlet tube 25 proceeding to the superheated steam manifold 26.

22 is the smoke tube receiving one of the (about) re -superheating low pressure elements 21 with its inlet tube 28 issuing from the low pressure manifold 29 and outlet tube 30 leading to the re-s-uperheated steam manifold 31;

Each of the smoke tubes I9 or 22 moreover receives, in its part adjacent to the smoke box, a re-superheating element constituted by asimple loop 32, 33 and 34, 35, also connected to the low pressure manifolds 29 and 3!.

For n superheating elements will thus ,be obtained about 271. re-superheating element's, roportion which is indispensable in order to have only an acceptable loss of head.

It is to be noted that all the re-superheating elements are not identical;

3 n 2 elements are constituted by a simple loop; spaced from the furnace, and

elements similar at all points to pressure The temperature will therefore not but it is very easy, by suitably arranging the re-superheated steam manifold, to obtain a suitable mixing of the steam before it is sent into the low pressure cylinders. 7

Furthermore, this inconvenience can beavoid; ed, at least to a certain extent, and the loss of head can be reduced at the same time in the elements concerned, by suitably choosing the dimensions of the constituent parts. I

What I claim as my invention and desire to secure by Letters Patent is: n t

1. A superheating device fordouble expansion steam engines, in particular forcompound locomotives, comprising a smoke tube, a high-pressure superheating element in the rear (fire-box) part of said smoke tube, a low-pressure single loop re-superheating element in the front (smoke- 3. A superheating device as claimed in claim 1, comprising a double loop high-pressure superheater.

4. A superheating device for steam engines comprising smoke tubes, main high pressure superheating elements and main low pressure superheating elements, each arranged in the rear (fire-box) part of a smoke tube, and auxiliary low-pressure superheating elements each arranged in the front (smoke-box) part of a smoke tube, behind a main high pressure element as well as behind a main low pressure element means to derive the steam flowing from the high-pressure superheating elements and from the highpressure cylinder and to direct it towards the low-pressure re-superheating elements and means to direct the steam thus re-superheated towards the low-pressure cylinder.

5. A superheating device for steam engines having high pressure cylinders and low pressure cylinders comprising smoke tubes, main low pressure re-superheating elements, main high pressure re-superheating elements twice as numerous as said main low pressure re-superheating elements, eachof said main low and high pressure re superli'eat-ing elements being arranged in the rear fire-box part of one 'of "said smoke tubes, auxiliary low pressure re-superhe'ating elements each arranged in the front smoke-box part of one of said smoke tubes, below each of said main high pressure elements as Well as below each of "Said inain low ressure elements, means to derive the steam flowing from said high pressure resuperheating elements and from said high-pressure cylinders and to direct it towards the low pressure re-sep'erne ung elements, and means'fio direct the steam rrom Said low pressure fie-511 1 361- heating elements towards said low-pressure'cylinders.

6. A re-superheating device as claimed in claim 1 comprising means to derive but a portion of the steam flowing from the high-pressure eynnder towards the 1ow-pressure re-superheating elements and means to mix the steam fraction thus re-superheate'd with the remainder of the steam flowing from the high-pressure superheating elements and 'from the high-pressure cylinder before directing it towards the low-pressure cylinder.

HOUL'ET.

REFERENCES err-En V The following references are of record in the file of this paliliiti UNITED STATES PATENTS 

